There has been proposed, for example in Patent Literature 1, that an acceleration sensor be configured using a semiconductor substrate formed by stacking a semiconductor layer on a support substrate. That is, in the acceleration sensor, a movable portion and a fixed portion are provided in a semiconductor layer, the movable portion including a movable electrode provided in a frame portion that is displaced in accordance with acceleration in a predetermined direction in a surface direction of the semiconductor layer, the fixed portion including a fixed electrode that faces the movable electrode.
In such an acceleration sensor, upon application of the acceleration in a predetermined direction, an interval between the movable electrode and the fixed electrode changes in accordance with the acceleration, and hence the acceleration is detected based on a capacitance between the movable electrode and the fixed electrode.